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M Shoji

Publications and source records attributed to M Shoji.

At least 73 records · Page 4Linked to original sources
PubMed2001

Discovery of a novel serine protease inhibitor utilizing a structure-based and experimental selection of fragments technique.

We report a set of strategies to develop novel ligands (Structure Based and Experimental Selection of Fragments: SbE-SF). First, a docking simulation utilizing DOCK3.5 is performed in order to screen the fragment database, which was generated with the in-house program FRAGMENT++ specifically for docking simulation purposes. Although the affinity of these small molecules (fragments) is expected to be low, the affinity of fragments selected by computation is assayed by experiment to determine which ones can be potent inhibitors. After determining such key fragments. additional fragments are attached to the key ones in order to increase the binding affinity,taking into account the binding modes predicted by computation. This method has been applied to a thrombin inhibitor study, resulting in the discovery of a novel inhibitor exhibiting pIC50 = 7.9.

Drug Design↗
PubMed2001

Mutations affecting nerve attachment of Caenorhabditis elegans.

Using a pan-neuronal GFP marker, a morphological screen was performed to detect Caenorhabditis elegans larval lethal mutants with severely disorganized major nerve cords. We recovered and characterized 21 mutants that displayed displacement or detachment of the ventral nerve cord from the body wall (Ven: ventral cord abnormal). Six mutations defined three novel genetic loci: ven-1, ven-2, and ven-3. Fifteen mutations proved to be alleles of previously identified muscle attachment/positioning genes, mup-4, mua-1, mua-5, and mua-6. All the mutants also displayed muscle attachment/positioning defects characteristic of mua/mup mutants. The pan-neuronal GFP marker also revealed that mutants of other mua/mup loci, such as mup-1, mup-2, and mua-2, exhibited the Ven defect. The hypodermis, the excretory canal, and the gonad were morphologically abnormal in some of the mutants. The pleiotropic nature of the defects indicates that ven and mua/mup genes are required generally for the maintenance of attachment of tissues to the body wall in C. elegans.

Animals↗
PubMed2001

The relation between plasma homocysteine concentration and methylenetetrahydrofolate reductase gene polymorphism in pregnant women.

OBJECTIVE: Our purpose was to clarify the influence of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism on plasma homocysteine (Hcy) concentrations during early pregnancy. METHODS: Between 1996 and 1998, Hcy concentration and MTHFR gene polymorphism were studied in 840 pregnant women between 6 to 12 weeks' gestation. Hcy concentration was measured by amino acid autoanalyzer (DLC-300, Nihon Denshi), and MTHFR genotypes were determined by the PCR/RFLP methods. Pregnancy outcomes were compared in association with Hcy concentration and MTHFR genotypes. RESULTS: A total of 816 of the 840 women were enrolled into the study because MTHFR genotypes were not available in 24 women. Genotypes of C677T in the MTHFR gene were CC: CT: TT (%) = 280 (34.3): 400 (49.0): 136 (16.7). Plasma Hcy concentration was significantly (p < 0.0001) higher in women with TT genotype than other genotypes [CC: CT: TT = 5.67 (2.8-10.6): 5.80 (2.5-20.1): 6.91 (3.5-20.9) nmol/ml, median (range)]. Women with hyperhomocysteinemia had severe preeclampsia (2 of 35 vs 5 of 714, p < 0.01) and stillbirth (2 of 35 vs 10 of 714, p < 0.05) more frequently than normohomocysteinemia. CONCLUSIONS: Plasma Hcy concentration during early pregnancy was higher in women with homozygote for the T677 allele in the MTHFR gene than other genotypes.

Adult↗
PubMed2001

Presynaptic inhibition of cerebellar GABAergic transmission by glutamate decarboxylase autoantibodies in progressive cerebellar ataxia.

Autoantibodies against glutamic acid decarboxylase (GAD) have been found in stiff-man syndrome, insulin dependent diabetes mellitus, and progressive cerebellar ataxia. A patient with progressive cerebellar ataxia is described who was positive for GAD autoantibodies, and had Sjögren's syndrome. Immunohistochemical studies using CSF and serum samples from the patient showed immunoreactivities in axon terminals of cerebellar GABAergic neurons. A whole cell patch clamp technique recording from rat cerebellar slices showed that the CSF, presumably through GAD autoantibodies, presynaptically inhibited GABAergic transmission. Intravenous administration of immunoglobulin failed to improve clinical symptoms and immunoreactivities examined after therapy. The findings suggest that GAD autoantibodies play a pathogenic part in reducing GABA release in in vitro slices.

Aged↗
PubMed2001

In vivo antiarrhythmic profile of AP-792 assessed in different canine arrhythmia models.

The antiarrhythmic effects of a novel antiarrhythmic drug AP-792, 4-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-[4-cyclohexylbutyl]piperidine hydrochloride, were analyzed using the epinephrine-, digitalis- and two-stage coronary ligation-induced canine ventricular arrhythmia models. Intravenous administration of AP-792 (0.3 or 1.0 mg/kg) effectively suppressed each of the ventricular arrhythmias, an action that resembles that of a typical cardioselective Ca2+ channel blocker, AH-1058. The antiarrhythmic action of AP-792 was slow in onset and longer-lasting than those in our previous studies using more than 50 antiarrhythmic drugs, including Na+ and Ca2+ channel blockers. These results suggest that AP-792 can become a unique long-acting antiarrhythmic drug.

Animals↗
PubMed2001

Cytochemical study of the involvement of cell organelles in formation and accumulation of fibrillar amyloid in the pancreas of NORbeta transgenic mice.

Phosphatase ultrastructural cytochemistry was used to evaluate the participation of cytoplasmic organelles in the accumulation of fibrillar amyloid beta (Abeta) in exocrine acinar cells and in macrophages of the pancreas of transgenic mice overexpressing a carboxy-terminal fragment of Abeta protein precursor (ABPP). Nucleoside diphosphatase (NDPase) and glucose-6-phosphatase (G6Pase) were used as cytochemical markers of the endoplasmic reticulum (ER), thiamine pyrophosphatase (TPPase) as a marker of the Golgi apparatus (GA), and acid phosphatase (AcPase) as a marker of lysosomes. Monoclonal antibody 4G8 raised against the 17-24 aa sequence of human Abeta protein was used for immunogold localization of fibrillar Abeta. The results of this study indicate that the formation of Abeta in acinar cells occurs directly in the vacuolar areas of the rough ER (RER) without evident participation of the elements of the GA, whereas an intimate structural relation with primary lysosomes suggests their role in modification or digestion of the deposited amyloid. In macrophages, fibrillar amyloid was present in numerous cytoplasmic vacuoles located frequently in close proximity to flattened saccules of the ER. This structural pattern revealed similarity to that observed previously in microglial cells producing fibrillar PrP amyloid in scrapie-infected mice and Abeta in brains of human elderly patients and in Alzheimer's type brain pathology.

Acid Anhydride Hydrolases↗
PubMed2001

Two Japanese CADASIL families with a R141C mutation in the Notch3 gene.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary disease characterized by recurrent transient ischemic attacks (TIA) and strokes, and vascular dementia with Notch3 gene mutations as the cause of the disease. To date, there are only a few Japanese families ever reported with a mutation in the gene. Here, we report two more Japanese CADASIL families carrying a missense mutation in the Notch3 gene (R141C) with a unique lesion in the corpus callosum. This is the first report of two unrelated Japanese CADASIL families with a R141C mutation in the Notch3 gene. Although the disease is very rare among the Japanese population, our result suggests a possible relationship of this particular mutation (R141C) with the lesions of the corpus callosum.

Agenesis of Corpus Callosum↗
PubMed2001

[Hypertension and gene polymorphisms].

For our understanding of the genetic factors of human essential hypertension, gene polymorphisms have played a significant role as DNA markers in association and linkage studies. We found positive linkages between hypertension and 4 gene polymorphisms including angiotensinogen Met235Thr, angiotensin converting enzyme I/D, aldosterone synthase CYP11B2 T-344C, and endothelial nitric oxide synthase Glu298Asp in the Aomori population. These results suggest that the 4 gene polymorphisms might be genetic risk factors for hypertension in this district. However, there has been a frustration with the inconsistencies of accumulated evidence. Because, the genetic associations tend to vary across race, ethnicity, and ecological states. Thus, the rates of racial inter-mixture can explain regional differences in disease susceptibility. We emphasize that human lineage based analysis across populations may lead to the better understanding of the variability.

Female↗
PubMed2000

JNK activation is associated with intracellular beta-amyloid accumulation.

c-Jun has been implicated in the pathogenesis of Alzheimer's disease (AD), but the upstream cascade leading to c-Jun activation in AD is not known. Activation of c-Jun N-terminal kinase (JNK) is obviously a candidate for the upstream event. We tested this possibility focusing on PS1-linked AD. First, we observed that JNK is actually activated in cerebral neurons of PS1-linked AD patients, using immunohistochemistry and Western blot analyses with anti-activated JNK antibodies. We analyzed the relationship between beta-amyloid (beta A) and JNK activation by using aged transgenic mice overexpressing mutant (M146L) PS1 and human AD brains. The mice showed no neuronal loss but a very few diffuse beta A deposits, corresponding to the early stage of PS1-linked AD brain. Some neurons were reactive for anti-beta A antibodies in the cerebral cortex. Interestingly, JNK activation was observed in neurons showing intracellular beta A immunoreactivity in transgenic mice. Association between intracellular beta A and JNK activation was confirmed in cortical neurons of sporadic and PS1-linked AD patients. Furthermore, introduction of beta A peptides into the primary culture cortical neurons induced JNK activation and cell death. Collectively, these results suggested that intracellular beta A accumulation might trigger JNK activation leading to neuronal death.

Alzheimer Disease↗
PubMed2000

Asymptomatic CTG expansion at the SCA8 locus is associated with cerebellar atrophy on MRI.

Spinocerebellar ataxia type 8 (SCA8) is the first example of dominantly inherited ataxia reported to be caused by a dynamic mutation of the untranslated CTG trinucleotide repeat. We performed genetic and clinical analyses of a family with an isolated case with young onset cerebellar ataxia carrying an expanded 95 CTA/CTG repeats, and revealed that the asymptomatic father was also carrying a much greater expansion of 136 repeats. This paternal transmission developed a large contraction of -41 CTG repeats. The ataxia patient showed almost pure cerebellar symptoms, and a cerebral MRI of the patient demonstrated significant atrophy of the cerebellar vermis and hemispheres with preservation of brainstem and cerebrum. Although the father did not show any neurological abnormalities, his MRI demonstrated mild atrophy of the cerebellar hemispheres. The genetic phenomenon on this family has not been observed in other types of SCAs, and this reduced penetrance may cause reproduction of sporadic SCA8 frequently. Therefore, we must perform careful interviews regarding family history, and suggest the genetic and neuroradiological investigations on family members when we encounter a sporadic patient with the CTG expansion at the SCA8 locus.

Adult↗
PubMed2000

Senile ocular amyloidosis in SAM and BALB/c strains of mice.

We investigated whether amyloid deposition can affect retinal atrophy in old SAMR1, SAMP1 and BALB/c mice. Immunohistochemistry revealed that old SAMP1 mice showed the deposition of the murine senile amyloid protein fibril, AApoA-II in the subconjunctival tissue, the vessel walls near the chamber angle, and the sheaths of the external ocular muscles and the conjunctival glands, but was never observed in the retina or the choroid. Although the old SAMR1 mice also showed a remarkable loss of retinal photoreceptor and ganglion cells, they never showed any amyloid deposition. The BALB/c strain did not showed any amyloid deposition either. Our data suggest that atrophy of the retina is not related to senile systemic amyloidosis in mice.

Aging↗
PubMed2000

Impaired neurotransmitter systems by Abeta amyloidosis in APPsw transgenic mice overexpressing amyloid beta protein precursor.

APPsw transgenic mice showing substantial features of brain Abeta amyloidosis such as senile plaques and behavioral abnormalities were examined by immunostaining to determine whether Abeta deposits could induce the subsequent disturbance of neurotransmitter systems including somatostatin, substance P and choline acetyltransferase (ChAT), which are prominent in the Alzheimer's disease brain. Somatostatin, substance P and ChAT disappeared in the areas of senile plaque and were accumulated in dystrophic neurites around the amyloid cores. These findings suggest a potential role of brain Abeta amyloidosis in disturbance of the neurotransmitter systems leading to memory disturbance of Alzheimer's disease.

Amygdala↗
PubMed2000

Amyloid beta protein starting pyroglutamate at position 3 is a major component of the amyloid deposits in the Alzheimer's disease brain.

The amyloid beta protein (Abeta) deposited in the Alzheimer's disease (AD) brain is heterogeneous at both its amino and carboxyl termini. Recent studies of the genetic forms of AD indicate that the aggregation and deposition of Abeta42 may be a common initiating event in all forms of AD. Here, we analyzed the amino termini of the Abeta species deposited in the AD brain, focusing specifically on species with amino-terminal pyroglutamate at position 3 (Abeta3(pE)). Immunocytochemical analysis of AD brains with an antibody specific for Abeta3(pE) confirmed that these species deposit in blood vessels and senile plaques. Using specific sandwich ELISAs, we determined the amounts of Abeta3(pE)-40 and Abeta3(pE)-42(43) in AD brain compared with other forms. This analysis showed that Abeta3(pE)-40 is closely correlated with the extent of Abeta deposition in blood vessels, whereas Abeta3(pE)-42(43) is not. In addition, Abeta3(pE)-42(43) is an important component of the Abeta deposited in senile plaques of the AD brain, constituting approximately 25% of the total Abeta42(43). In vitro comparison of Abeta1-42 and Abeta3(pE)-42 showed that Abeta3(pE)-42 is highly prone to oligomerization. These findings suggest that Abeta3(pE)-42 may be particularly important in AD pathogenesis.

Aged↗
PubMed2000

Positive association of endothelial nitric oxide synthase gene polymorphism with hypertension in northern Japan.

Vascular endothelial cells produce nitric oxide (NO), which contributes to the regulation of blood pressure and regional blood flow. Although Endothelial NO synthase (eNOS) gene polymorphisms have been shown to have a positive association with coronary artery disease, the linkage between eNOS gene polymorphisms and hypertension has been controversial. In the present study, therefore, we identified genotypes for Glu298Asp and variable number tandem repeats in intron 4 (4b/a) in 183 hypertensive and 193 normotensive populations. The Glu298Asp variant had a significant association with hypertension (odds ratio, 1.8; 95% confidence interval, 1.1-3.0). The allele frequencies of 298Asp for Glu298 in hypertensive patients were significantly higher than those in normotensive subjects (0.128 vs 0.080, p<0.05). Diastolic and mean arterial blood pressures were significantly higher in hypertensive subjects with the 298Asp allele than those without the variant allele (p<0.05). However, disequilibrium of 4b/a polymorphism was absent between these two groups. These results suggest that the Glu298Asp variant may be a genetic susceptibility factor for hypertension.

Aged↗
PubMed2000

Simultaneous suppression of cdc2 and cdk2 activities induces neuronal differentiation of PC12 cells.

The involvement of cdc2 and cdk2 during neuronal differentiation in rat pheochromocytoma PC12 cells was examined. When PC12 cells were cultured with nerve growth factor (NGF), expression of cdc2 decreased significantly after day 5, while expression of cdk2 decreased gradually after day 7. Cells overexpressing cdc2 or cdk2 were resistant to NGF-induced differentiation and growth suppression, and maintained high cdc2 or cdk2 kinase activity, respectively, during NGF treatment. In contrast, the NGF-treated parental cells showed a marked decline in these kinase activities after day 3. When PC12 cells were treated with specific inhibitors of cdc2/cdk2 (butyrolactone-I, olomoucin), they showed marked neurite extension and up-regulation of microtubule-associated protein 2 expression. In addition, treatment with mixtures of antisense oligonucleotides for cdc2 and cdk2 resulted in down-regulation of both cdc2 and cdk2 kinase activities as well as significant neurite outgrowth and up-regulation of microtubule-associated protein 2 expression. However, neurite outgrowth was not observed in cells treated with either single antisense oligonucleotide, or antisense cdc2 + cdk4 or cdk2 + cdk4 oligonucleotide mixtures. These results suggest that simultaneous down-regulation of cdc2 and cdk2 activity is sufficient and necessary for neuronal differentiation in PC12 cells.

Animals↗
PubMed2000

cDNAs encoding the baboon thrombin receptor indicate a primate transcription start site upstream of putative sites reported for the human gene.

Two cDNAs encoding the thrombin receptor of baboon vascular smooth muscle cells have 5'-untranslated regions that begin upstream of multiple putative transcription initiation sites reported for the closely related human receptor gene. The extent of these baboon 5'-untranslated cDNA regions and their close similarity to the corresponding human sequences suggest that there is only one transcription initiation site of the primate thrombin receptor gene, which might be linked to a typical TATA-box previously identified in the upstream region of the human gene. It is possible that all primates have a unique thrombin receptor gene transcription start site. Inferences drawn from the baboon system may be usefully extrapolated to the human, in view of the extensive similarities seen between the nucleotide sequences of baboon and human thrombin receptor gene sequences in the 5'- untranslated and coding regions. The extents of the 5'-untranslated region of the baboon cDNAs argue that the "multiple" transcription start sites identified for the human gene are artifactual. The striking differences in the reported baboon and human transcription start sites warrant further investigation in view of the significant role played by the thrombin receptor in numerous vascular and cellular growth responses.

Amino Acid Sequence↗
PubMed2000

Molecular and clinical analyses of spinocerebellar ataxia type 8 in Japan.

OBJECTIVE: To clarify the molecular and clinical features of the newly identified spinocerebellar ataxia type 8 (SCA8). METHODS: We analyzed the CTG repeat region of the SCA8 gene in a series of Japanese patients with cerebellar ataxia. We also investigated the frequency of the CTG repeat length in Japanese normal elderly subjects older than age 79. Morphometric measurements on the cerebral MRI were compared between patients with SCA8 and SCA6. RESULTS: The number of the combined CTA/CTG repeats of six affected SCA8 alleles was 106.3+/-24.4 (mean +/- SD) ranging from 89 to 155 and that of normal elderly subjects was 24.3+/-4.4 (n = 104 alleles) ranging from 15 to 34. The mean age at onset of the SCA8 cases was 53.8+/-19.7 years, with a range from 20 to 73 years. One father and daughter from an SCA8 family showed remarkable paternal anticipation. The number increase from father to daughter was + 16 CTG repeats, with a 31-year acceleration of onset. The six identified SCA8 patients were clinically characterized by high frequencies of incoordination of trunk and limbs, ataxic dysarthria, impaired smooth pursuit, and horizontal nystagmus, and the MRI showed significant atrophy of the cerebellar vermis and hemispheres compared with that of normal controls. There was no significant difference between SCA8 and SCA6 on the morphometric MRI study. CONCLUSIONS: The CTG repeat expansions in the SCA8 alleles were much greater than the range of repeats in normal elderly subjects. The SCA8 phenotype manifested by cerebellar symptoms and atrophy corresponded to features of the autosomal dominant cerebellar ataxia type III (ADCA III).

Adult↗